Based on what we see in terms of narrative, he hasn't taken anything. They still took the herb to him as a kind of bargaining chip towards the end of the film. And he didn't drink any power removing elixir when challenging T'Challa, IIRC.

That being said, he is freakishly strong for a human, being able to manhandle opponents in a manner not that far off from actual super soldiers/people who took the herb.